US9737229B1ActiveUtility
Noninvasive electrocardiographic method for estimating mammalian cardiac chamber size and mechanical function
Est. expiryJun 4, 2033(~6.9 yrs left)· nominal 20-yr term from priority
Inventors:Sunny GuptaDerek Vincent ExnerMohsen Najafi YazdiTimothy William Fawcett BurtonShyamlal Ramchandani
A61B 5/349A61B 5/7264A61B 5/04525A61B 5/0452A61B 2576/023A61B 5/7275A61B 5/35A61B 5/341A61B 5/1075A61B 5/029
89
PatentIndex Score
36
Cited by
19
References
15
Claims
Abstract
The present disclosure generally relates to systems and methods of a noninvasive technique for characterizing cardiac chamber size and cardiac mechanical function. A mathematical analysis of three-dimensional (3D) high resolution data may be used to estimate chamber size and cardiac mechanical function. For example, high-resolution mammalian signals are analyzed across multiple leads, as 3D orthogonal (X,Y,Z) or 10-channel data, for 30 to 800 seconds, to derive estimates of cardiac chamber size and cardiac mechanical function. Multiple mathematical approaches may be used to analyze the dynamical and geometrical properties of the data.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method to noninvasively estimate cardiac chamber size and cardiac mechanical function, including left ventricular ejection fraction, the method comprising:
obtaining, by a processor, three-dimensional (3D) orthogonal data from a measurement of one more surface electrical signals of a subject, wherein the three-dimensional (3D) orthogonal data is derived from measurements acquired via noninvasive equipment configured to measure electrical properties of the heart;
determining, by the processor, via a numerical integral operation of one or more vectorcardiogram components associated with a vectorcardiogram of the 3D orthogonal data, i) one or more first parameters selected from the group consisting of a sum QRST integral parameter, a 3D volume integral parameter, a spatial QRST angle parameter, a 3D QRS loop volume parameter, a 3D T-loop volume parameter, a spatial ventricular gradient parameter, a spatial ventricular gradient azimuth parameter, a spatial ventricular gradient elevation parameter, and ii) one or more second parameters associated with beat-to-beat variability of the one or more first parameters; and
determining, by the processor, an estimate cardiac chamber size parameter by applying the one or more first parameters and the one or more second parameters in one or more first models associated with the cardiac chamber size; and
determining, by the processor, one or more cardiac chamber mechanical function parameters by applying the one or more first parameters and the one or more second parameters in one or more second models associated with each cardiac chamber mechanical functions; and
cause, by the processor, the estimate cardiac chamber size parameter and the one or more cardiac chamber mechanical function parameters to be presented in a graphical user interface.
2. The method of claim 1 , wherein the vectorcardiogram comprises a 12- or N-dimensional phase space transformation of the 3D orthogonal data.
3. The method of claim 1 , wherein the 3D orthogonal data is obtained via an ECG measurement equipment that includes a surface ECG instrument.
4. The method of claim 3 , wherein the 3D orthogonal data is obtained via the ECG measurement equipment over a time period of about 30 seconds to about 800 seconds.
5. The method of claim 1 , wherein the one or more cardiac chamber mechanical function parameters are selected from the group consisting of a cardiac output parameter, a stroke volume parameter, an end-diastolic volume parameter, an end-systolic volume parameter, and an ejection fraction parameter.
6. The method of claim 1 , wherein the presented one or more cardiac chamber mechanical function parameters are subsequently used to screen patients for structural heart disease.
7. The method of claim 1 , wherein the determined one or more cardiac chamber mechanical function parameters comprise ventricular mechanical cardiac function values, the method further comprising using a variability of the ventricular mechanical cardiac function values among a plurality of heart beats in the 3D orthogonal data to determine presence of a decline in cardiac function to assess risk of clinical events.
8. The method of claim 7 , wherein the ventricular mechanical cardiac function values include cardiac output, stroke volume, end-diastolic volume, end-systolic volume and ejection fraction.
9. The method of claim 1 , wherein the determined one or more cardiac chamber mechanical function parameters comprise atrial mechanical cardiac function values, the method further comprising using a variability of the atrial mechanical cardiac function values among a plurality of heart beats in the 3D orthogonal data to determine presence of a reduced atrial cardiac function and to assess risk of clinical events.
10. The method of claim 1 , wherein the Sum QRST integral parameter is determined by:
∫
t
1
t
2
V
x
+
∫
t
1
t
2
V
y
+
∫
t
1
t
2
V
z
wherein V x , V y , and V z are the one or more vectorcardiogram components, and wherein t 2 −t 1 comprises a measurement time window for the 3D orthogonal data.
11. The method of claim 1 , wherein the 3D QRS loop volume parameter, the 3D T-loop volume parameter, and the 3D volume integral parameter are determined by:
∫
t
1
t
2
V
x
*
∫
t
1
t
2
V
y
*
∫
t
1
t
2
V
z
wherein V x , V y , and V z are the one or more vectorcardiogram components, and wherein t 2 −t 1 comprises a measurement time window for the 3D orthogonal data.
12. The method of claim 1 , wherein the spatial ventricular gradient (SVG) parameter is determined by:
(
∫
t
1
t
2
V
x
)
2
+
(
∫
t
1
t
2
V
y
)
2
+
(
∫
t
1
t
2
V
z
)
2
wherein V x , V y , and V z are the one or more vectorcardiogram components, and wherein t 2 −t 1 comprises a measurement time window for the 3D orthogonal data.
13. The method of claim 1 , wherein the spatial ventricular gradient azimuth parameter is determined by:
arc
tan
∫
t
1
t
2
V
z
t
1
t
2
v
x
dt
wherein V x and V z are the one or more vectorcardiogram components, and wherein t 2 −t 1 comprises a measurement time window for the 3D orthogonal data.
14. The method of claim 1 , wherein the spatial ventricular gradient elevation parameter is determined by:
arc
cos
∫
t
1
t
2
V
y
(
∫
t
1
t
2
V
x
)
2
+
(
∫
t
1
t
2
V
y
)
2
+
(
∫
t
1
t
2
V
z
)
2
wherein V x , V y , and V z are the one or more vectorcardiogram components, and wherein t 2 −t 1 comprises a measurement time window for the 3D orthogonal data.
15. The method of claim 1 , wherein the one or more first parameters comprise spatial gradient parameters, including a peak amplitude of the vectorcardiogram, a size of a QRS vector loop of the vectorcardiogram, an angle of depolarization, an angle of repolarization, and a voltage spatial gradient.Cited by (0)
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